1. Field of Invention
This invention relates to ballistic armor. More specifically, this invention relates to an armor system utilizing a multi-layer structure incorporating glass-ceramics and laminates.
2. Description of the Related Art
In order to provide protection of personnel and equipment from ballistic projectiles, explosive ordnance, and forces and objects from detonation of improvised explosive devices (collectively hereinafter “projectiles”), it is necessary to provide a means of disbursing the kinetic energy of such projectiles to prevent them from reaching their target. Although this may be accomplished by interposing a large mass of any of a number of different materials between the target and the incoming projectile, experience has shown that a much more efficient means of energy disbursement is provided by suitably engineered ballistic armor structures wherein layers of different materials act to disrupt and disperse the energy of an incoming projectile. Such structures strive to maximize the amount of material which may be acted upon to absorb and disburse the energy of the projectile, while at the same time breaking or deforming the projectile and distributing these resulting fragments into a wider area. Such structures further strive to minimize the total amount of materials required for the protection of a specific area.
Ballistic armor structures generally contain one or more layers of material engineered to spread the force of the impact by deforming, deflecting, or fragmenting the ballistic projectile while the ballistic armor itself undergoes deformation or localized fragmentation. The deformation and localized fragmentation processes of the ballistic armor structure absorb a large portion of energy from the projectile while simultaneously spreading the impacted area to involve more material in successive layers. Both hardness and toughness of the ballistic armor structure are required for these functions.
In the field of ballistic armor structures, the initial layer of material used to disrupt the incoming ballistic projectile is often referred to as the “strike face,” or alternatively, the “hard face.” The hard face is typically a layer of relatively hard and tough material designed to deform, and in some cases fragment, to absorb at least some of the energy of the incoming projectile, thereby distributing the projectile's energy. Following the hard face are other layers specifically designed to absorb the remaining energy of the impacting material and pieces of the previous hard face. These layers are often referred to as the “backing” or “catcher.”
The process of energy absorption and disbursement of the incoming projectile by the ballistic armor structure is generally intended to result in deformation, displacement and/or localized fracture of the hard face, and deformation and/or displacement of the backing, but without penetration through the ballistic armor structure by any fragments of the ballistic projectile. Selection of materials for these distinct functions and careful attention to construction and coupling of the various layers is essential to optimizing performance of the ballistic armor structure.
In many armor applications, traditional materials such as steel offer some level of protection from ballistic projectiles and shell fragments. However, great advances have been made in selection of materials for optimizing the performance of ballistic armor structures. Use of high-strength, hard, and in some cases “tough” ceramics like aluminum oxide, boron carbide, titanium diboride and silicon carbide for the hard face; and rigid or soft laminates of fibrous materials such as fiberglass, aramid, or polyethylene fiber for the backing have greatly reduced the mass and bulk of protective structures. These advances, unfortunately, are limited in the amount of ballistic energy that can reasonably be dissipated, and therefore these advances have not been readily applicable to those situations in which protection against a significant ballistic threat is required.
Accordingly, there is a need for improvement in lighter weight, thinner ballistic armor to meet the increasing threats posed by newer, more energetic, and more powerful projectiles. Specifically, there is a need for improvement in lighter weight, thinner ballistic armor which can disrupt and disburse projectiles emanating from significant ballistic threats, which can easily be utilized by personnel, vehicles, equipment, buildings, and the like.